Think you know about poinsettia flowers? Below I make five points about these iconic holiday plants that might surprise many people. Let’s put them in question form, first, so that you can see how astute you are on the subject:

1. Is “poinsettia” the botanical or the common name for the plants?

2. Why do they flower around Christmastime?

3. What color is the true flower?

4. Can poinsettias be harmful to your health?

5. What is the correct pronunciation for “poinsettia?”

Plant taxonomy:

Plant taxonomy classifies Christmas poinsettias as Euphorbia pulcherrima, literally, “the most beautiful Euphorbia” (Euphorbia is not only a genus name, it is also the name of a large plant family).

If Euphorbia pulcherrima is the scientific name for these plants, one may well ask how their common name, which looks like it should be a scientific name, is derived. Well, the common name derives from the fact that Joel Roberts Poinsett, the first U.S. Ambassador to Mexico, introduced the first specimens to North America (1828).

Plant type:

Euphorbia pulcherrima is a sub-tropical plant, native to Mexico. There, it is a deciduous flowering shrub, growing up to 10 feet in height. Intolerant of the cold, in the north it is grown almost exclusively indoors. The plants are raised in greenhouses — it’s big $$ business — to be sold as potted flowers for the holidays. Enormously popular holiday gifts, they are treated by most of their recipients as indoor houseplants.

The salient point about their status as sub-tropical plants is that, when transporting them in cold weather — say, from a florist shop to your home — they should be wrapped for protection.

USDA plant hardiness zones:

Euphorbia pulcherrima can be grown as a perennial in zone 10 and higher (e.g., south Florida).

Characteristics:

When mention is made of poinsettia plants, most people think of the color red. But the “flowers” also come in white, yellow, pink and in color combinations. The “marbled” type is one of the most fascinating. Available from florists in a variety of sizes, an average height for potted poinsettia plants is perhaps about 2 feet (not counting the container).

Sun and soil requirements:

If you want to treat poinsettia flowers as annuals, you can grow them outside for a bit of extra greenery. But frankly, they aren’t anything special without the colors that nurseries artificially induce them to put on around Christmas. You can move them outdoors after all danger of frost has passed. Grow them in well-drained soil and in a sunny spot that receives a fair amount of shade in the afternoon. Water needs: moderate to high.

Getting Christmas poinsettias to flower the next year:

The only reason you can buy them at the florist shop in bloom during the Yuletide season is that greenhouse operators have manipulated their bud set. Flowering is dictated by number of daylight hours available. If you wish to replicate this “forcing” and get your plant to bloom again, you’ll need “about 10 weeks with 12 hours or less of sunlight per day.” Sound like a lot of work? You bet it is. In other words: getting them to flower again is a real pain — something best left to professional greenhouse operators.

The “flowers” of Christmas poinsettia plants:

When laymen speak of the “flowers” on poinsettia plants, what they’re actually referring to are petal-like leaves known as “bracts.” Euphorbia pulcherrima does have flowers, but these green and yellow flowers are small — and certainly not a noteworthy feature. The colorful bracts form around (and just below) these inconsequential flowers.

The myth of poinsettia plants being poisonous — are they harmful?:

Regarding the toxicity of Euphorbia pulcherrima, one could say, “A new myth has grown up in the process of dispelling an old myth.” Let me explain:

As many have pointed out, it is a myth that poinsettia plants are deadly poisonous if a child or pet eats the leaves, but that doesn’t mean that the leaves should intentionally be eaten, either. But because this fact is so widely known now, I fear that a new myth has arisen: namely, that no health issues whatsoever surround the annual displaying of poinsettia plants. The fact is, this Christmas icon can be quite harmful to some people; and the harm derives not from eating the leaves but simply from being around poinsettia plants.

Why? Because the milky sap that oozes from the branches can result in contact dermatitis in some people. So unless you like to itch, avoid the sap, in case you’re one of those prone to develop this rash. At the very least, be sure not to touch your eyes after touching the sap. The harm some people suffer from being around poinsettia plants can be even worse (e.g., difficulty breathing).

Spelling and Pronunciation:

We can thank the derivation of the plant’s name from Ambassador “Poinsett” for the numerous misspellings that abound. People seem intent on spelling the name “poinsetta,” for example (dropping the i at the end). Another common misspelling involves inserting an extra t (the fact that “points” is a nickname commonly used in the florist and nursery trades probably does not help matters here). “Poinsetters” is a spelling even more off-base, but it is also more common than one might imagine.

Why couldn’t this guy have been named Jones?

Such misspellings have spawned mispronunciations (or is it the other way around?) Dictionaries list poin-SET-ee-uh and poin-SET-uh as acceptable pronunciations. However, both folks in the industry and their customers regularly insert a “T” after the “N,” so that the word most often ends up being pronounced, point-SET-uh.

Christmas poinsettia legend:

The legend regarding Euphorbia pulcherrima begins long ago with a peasant girl in Mexico, faced with a problem on Holy Night: she lacked the means to contribute a gift in the Christ Child ceremony at the church, as all the other children would be doing. The girl was, however, reassured that, to use a modern expression, “it’s the thought that counts.”

Taking this advice, she picked some roadside weeds on the way to her church to make a bouquet. However when she arrived at the church and it was time for her to present her gift, the bouquet of weeds was transformed into something much more colorful — red Christmas poinsettias. Thus was born an enduring Christmas tradition, as we continue to associate these “flowers” with the holiday season.

Merry Christmas from my family to yours, and happy gardening!

Jimmie

Send your landscaping and gardening questions to Jimmie Gibson Jr. at http://www.absolutelybushedlandscaping.com or in care of the Prosper Press at mwilcox@prosperpress.com. Jimmie is the owner of Absolutely Bushed Landscaping Company. He is a resident in Prosper. His landscaping and gardening column runs every other week in the Prosper Press.